[RFC linux v1 2/2] drivers: occ hwmon - isolate bus transfer protocol

Andrew Jeffery andrew at aj.id.au
Tue Oct 11 12:51:31 AEDT 2016


On Mon, 2016-10-10 at 14:07 -0500, eajames.ibm at gmail.com wrote:
> From: "Edward A. James" <eajames at us.ibm.com>
> 

Again, this needs a commit message. A 1300 line change needs some
supporting words.

> Signed-off-by: Edward A. James <eajames at us.ibm.com>
> ---
>  drivers/hwmon/Kconfig          |  13 +-
>  drivers/hwmon/Makefile         |   2 +-
>  drivers/hwmon/occ/Kconfig      |  15 +
>  drivers/hwmon/occ/Makefile     |   1 +
>  drivers/hwmon/occ/occ.c        | 127 ++++++
>  drivers/hwmon/occ/occ.h        |  50 +++
>  drivers/hwmon/occ/occ_i2c.c    | 191 ++++++++
>  drivers/hwmon/occ/power8_occ.c | 970 ++++++++++++++++-------------------------
>  drivers/hwmon/occ/power8_occ.h |  24 +
>  9 files changed, 792 insertions(+), 601 deletions(-)
>  create mode 100644 drivers/hwmon/occ/Kconfig
>  create mode 100644 drivers/hwmon/occ/Makefile
>  create mode 100644 drivers/hwmon/occ/occ.c
>  create mode 100644 drivers/hwmon/occ/occ.h
>  create mode 100644 drivers/hwmon/occ/occ_i2c.c
>  create mode 100644 drivers/hwmon/occ/power8_occ.h
> 
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 3b34ba9..0ef3690 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1216,18 +1216,7 @@ config SENSORS_NSA320
>  	  This driver can also be built as a module. If so, the module
>  	  will be called nsa320-hwmon.
>  
> -config SENSORS_POWER8_OCC_I2C
> -	tristate "Power8 On Chip Controller i2c driver"
> -	depends on I2C
> -	help
> -	  If you say yes here you get support to monitor Power8 CPU
> -	  sensors via the On Chip Controller (OCC) over the i2c bus.
> -
> -	  Generally this is used by management controllers such as a BMC
> -	  on an OpenPower system.
> -
> -	  This driver can also be built as a module. If so, the module
> -	  will be called power8_occ_i2c.
> +source drivers/hwmon/occ/Kconfig
>  
>  config SENSORS_PCF8591
>  	tristate "Philips PCF8591 ADC/DAC"
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index c0f3201..7f61e31 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -127,7 +127,6 @@ obj-$(CONFIG_SENSORS_NCT7802)	+= nct7802.o
>  obj-$(CONFIG_SENSORS_NCT7904)	+= nct7904.o
>  obj-$(CONFIG_SENSORS_NSA320)	+= nsa320-hwmon.o
>  obj-$(CONFIG_SENSORS_NTC_THERMISTOR)	+= ntc_thermistor.o
> -obj-$(CONFIG_SENSORS_POWER8_OCC_I2C)	+= power8_occ_i2c.o
>  obj-$(CONFIG_SENSORS_PC87360)	+= pc87360.o
>  obj-$(CONFIG_SENSORS_PC87427)	+= pc87427.o
>  obj-$(CONFIG_SENSORS_PCF8591)	+= pcf8591.o
> @@ -165,6 +164,7 @@ obj-$(CONFIG_SENSORS_WM831X)	+= wm831x-hwmon.o
>  obj-$(CONFIG_SENSORS_WM8350)	+= wm8350-hwmon.o
>  
>  obj-$(CONFIG_PMBUS)		+= pmbus/
> +obj-$(CONFI_OCC)		+= occ/

As mentioned on the previous patch, please move some of these changes
to address its build issues.

>  
>  ccflags-$(CONFIG_HWMON_DEBUG_CHIP) := -DDEBUG
>  
> diff --git a/drivers/hwmon/occ/Kconfig b/drivers/hwmon/occ/Kconfig
> new file mode 100644
> index 0000000..628fd6e
> --- /dev/null
> +++ b/drivers/hwmon/occ/Kconfig
> @@ -0,0 +1,15 @@
> +#
> +# On Chip Controller configuration
> +#
> +
> +config OCC
> +	tristate "On Chip Controller driver"
> +	help
> +	  If you say yes here you get support to monitor Power CPU
> +	  sensors via the On Chip Controller (OCC).
> +
> +	  Generally this is used by management controllers such as a BMC
> +	  on an OpenPower system.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called occ.
> diff --git a/drivers/hwmon/occ/Makefile b/drivers/hwmon/occ/Makefile
> new file mode 100644
> index 0000000..05b5031
> --- /dev/null
> +++ b/drivers/hwmon/occ/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_OCC) += occ.o occ_i2c.o power8_occ.o
> diff --git a/drivers/hwmon/occ/occ.c b/drivers/hwmon/occ/occ.c
> new file mode 100644
> index 0000000..9eeacca
> --- /dev/null
> +++ b/drivers/hwmon/occ/occ.c
> @@ -0,0 +1,127 @@
> +/*
> + * occ.c - hwmon OCC driver
> + *
> + * This file contains common methods between different host systems and bus
> + * protocols.
> + *
> + * Copyright 2016 IBM Corp.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +
> +#include "occ.h"
> +#include "power8_occ.h"
> +
> +static ssize_t show_occ_online(struct device *dev,
> +			       struct device_attribute *attr, char *buf)
> +{
> +	struct occ_driver *driver = (struct occ_driver *)dev_get_drvdata(dev);
> +
> +	return snprintf(buf, PAGE_SIZE - 1, "%lu\n", driver->occ_online);
> +}
> +
> +static ssize_t store_occ_online(struct device *dev,
> +				struct device_attribute *attr,
> +				const char *buf, size_t count)
> +{
> +	struct occ_driver *driver = (struct occ_driver *)dev_get_drvdata(dev);
> +	unsigned long val;
> +	int rc;
> +
> +	rc = kstrtoul(buf, 10, &val);
> +	if (rc)
> +		return rc;
> +
> +	if (val == 1) {
> +		if (driver->occ_online)
> +			return count;
> +
> +		driver->hwmon = hwmon_device_register(dev);
> +		if (IS_ERR(driver->hwmon))
> +			return PTR_ERR(driver->hwmon);
> +
> +		rc = occ_init(driver);
> +		if (rc) {
> +			hwmon_device_unregister(driver->hwmon);
> +			driver->hwmon = NULL;
> +			return rc;
> +		}
> +	} else if (val == 0) {
> +		if (!driver->occ_online)
> +			return count;
> +
> +		occ_exit(driver);
> +		hwmon_device_unregister(driver->hwmon);
> +		driver->hwmon = NULL;
> +	} else
> +		return -EINVAL;
> +
> +	driver->occ_online = val;
> +	return count;
> +}
> +
> +static DEVICE_ATTR(online, S_IWUSR | S_IRUGO, show_occ_online,
> +		   store_occ_online);
> +
> +/*
> + * occ_common_probe - hardware agnostic initialization method
> + * @dev: device handle for transfer protocol
> + * @bus_ops: transfer methods to communicate with the OCC
> + * @bus: private handle for transfer protocol
> + *
> + * this initializes common aspects of the hwmon driver across bus protocols and
> + * host systems.
> + *
> + * returns negative errno on failure or 0 on success
> + */
> +int occ_probe(struct device *dev, struct occ_bus_ops bus_ops, void *bus)
> +{
> +	struct occ_driver *driver = devm_kzalloc(dev,
> +						 sizeof(struct occ_driver),
> +						 GFP_KERNEL);
> +
> +	if (!driver)
> +		return -ENOMEM;
> +
> +	driver->bus = bus;
> +	driver->bus_ops = bus_ops;
> +
> +	dev_set_drvdata(dev, driver);
> +
> +	return device_create_file(dev, &dev_attr_online);
> +}
> +
> +/*
> + * occ_common_remove - hardware agnostic exit method
> + * @dev: device handle for transfer protocol
> + *
> + * returns negative errno on failure or 0 on success
> + */
> +int occ_remove(struct device *dev)
> +{
> +	struct occ_driver *driver = dev_get_drvdata(dev);
> +
> +	device_remove_file(dev, &dev_attr_online);
> +
> +	if (driver->hwmon) {
> +		hwmon_device_unregister(driver->hwmon);
> +		occ_remove_hwmon_attrs(driver);
> +	}
> +
> +	return 0;
> +}
> diff --git a/drivers/hwmon/occ/occ.h b/drivers/hwmon/occ/occ.h
> new file mode 100644
> index 0000000..788339f
> --- /dev/null
> +++ b/drivers/hwmon/occ/occ.h
> @@ -0,0 +1,50 @@
> +/*
> + * power_occ.h - hwmon OCC driver
> + *
> + * This file contains data structures and function prototypes for common access
> + * between different bus protocols and host systems.
> + *
> + * Copyright 2016 IBM Corp.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#ifndef __OCC_H__
> +#define __OCC_H__
> +
> +struct device;
> +
> +/*
> + * occ_bus_ops - represent the low-level transfer methods to communicate with
> + * the OCC.
> + */
> +struct occ_bus_ops {
> +	ssize_t (*read)(void *bus, void *buf, size_t count);
> +	ssize_t (*write)(void *bus, void *buf, size_t count);
> +	int (*getscom)(void *bus, uint32_t address, uint8_t *data, int offset);

You should use kernel types here e.g. u32 and u8. And for below with
putscom(), and in the associated implementations:

> +	int (*putscom)(void *bus, uint32_t address, uint8_t data0,
> +		       uint8_t data1);

However, having read down a little it seems that this is a product of
the existing code. Given my other suggestions w.r.t. breaking up this
patch, the type fixes should be done as a separate change. Bear that in
mind, as I've made further comments on types thoughout the patch.

More importantly, my gut feeling is we are mixing abstractions here.
Maybe [gs]etscom() should be moved out of struct occ_bus_ops. I'll read
on...

> +};
> +
> +/*
> + * occ_driver - structure to store all global driver data
> + */
> +struct occ_driver {
> +	void *bus;
> +	struct occ_bus_ops bus_ops;
> +	struct device *hwmon;
> +	bool occ_online;
> +};
> +
> +int occ_probe(struct device *dev, struct occ_bus_ops bus_ops, void *bus);
> +int occ_remove(struct device *dev);
> +
> +#endif /* __OCC_H__ */
> diff --git a/drivers/hwmon/occ/occ_i2c.c b/drivers/hwmon/occ/occ_i2c.c
> new file mode 100644
> index 0000000..739642b
> --- /dev/null
> +++ b/drivers/hwmon/occ/occ_i2c.c
> @@ -0,0 +1,191 @@
> +/*
> + * occ_i2c.c - hwmon OCC driver
> + *
> + * This file contains the i2c layer for accessing the OCC over i2c bus.
> + *
> + * Copyright 2016 IBM Corp.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +
> +#include "occ.h"
> +
> +#define OCC_I2C_NAME	"occ-i2c"
> +
> +#define OCC_DATA_MAX	4096
> +#define I2C_READ_ERROR	1
> +#define I2C_WRITE_ERROR	2
> +
> +/*
> + * occ_i2c_read - wrapper for i2c_master_recv
> + * @bus: handle to slave device
> + * @buf: where to store data read from slave
> + * @count: how many bytes to read
> + *
> + * Returns negative errno or else the number of bytes successfully read
> + */
> +ssize_t occ_i2c_read(void *bus, void *buf, size_t count)
> +{
> +	struct i2c_client *client = bus;
> +
> +	WARN_ON(count > OCC_DATA_MAX);
> +
> +	dev_dbg(&client->dev, "i2c_read: reading %zu bytes @0x%x.\n",
> +		count, client->addr);
> +	return i2c_master_recv(client, buf, count);
> +}
> +
> +/*
> + * occ_i2c_read - wrapper for i2c_master_send
> + * @bus: handle to slave device
> + * @buf: data that will be written to the slave
> + * @count: how many bytes to write
> + *
> + * Returns negative errno or else the number of bytes successfully written
> + */
> +ssize_t occ_i2c_write(void *bus, void *buf, size_t count)
> +{
> +	struct i2c_client *client = bus;
> +
> +	WARN_ON(count > OCC_DATA_MAX);
> +
> +	dev_dbg(&client->dev, "i2c_write: writing %zu bytes @0x%x.\n",
> +		count, client->addr);
> +	return i2c_master_send(client, buf, count);
> +}
> +
> +/*
> + * occ_getscom - helper function for scom read over i2c to OCC
> + * @bus: handle to slave device
> + * @address: address
> + * @data: where to store data read from slave
> + * @offset: offset into data pointer

The documentation should make clear that the length of the data buffer
must be equal or longer than (offset + 8).


> + *
> + * Returns 0 on success or -1 on read error, -2 on write error
> + */
> +int occ_getscom(void *bus, uint32_t address, uint8_t *data, int offset)

As mentioned in the header use kernel types: u32, u8 etc. Does offset
need to be negative? Maybe size_t is better. Goes for occ_putscom() as
well (and possibly elsewhere).

> +{
> +	ssize_t rc;
> +	char buf[8];

buf should likely be u8, given the "data" formal parameter is unsigned.

> +	int i;
> +
> +	/* P8 i2c slave requires address to be shifted by 1 */
> +	address = address << 1;
> +
> +	rc = occ_i2c_write(client, &address, sizeof(uint32_t));

sizeof(u32)

> +
> +	if (rc != sizeof(address))
> +		return -I2C_WRITE_ERROR;
> +
> +	rc = occ_i2c_read(bus, buf, sizeof(buf));

What's the justification for the read() and write() callbacks in struct
bus_ops if we're just going to invoke the transport functions directly?

> +	if (rc != sizeof(buf))
> +		return -I2C_READ_ERROR;
> +
> +	for (i = 0; i < 8; i++)
> +		data[offset + i] = buf[7 - i];

Perhaps you should use the endian helpers?

> +
> +	return 0;
> +}
> +
> +/*
> + * occ_putscom - helper function for scom write over i2c to OCC
> + * @bus: handle to slave device
> + * @address: address
> + * @data0: first data byte to write
> + * @data1: second data byte to write
> + *
> + * Returns 0 on success or -2 on error
> + */
> +int occ_putscom(void *bus, uint32_t address, uint32_t data0, uint32_t data1)
> +{
> +	uint32_t buf[3];
> +	ssize_t rc;
> +
> +	/* P8 i2c slave requires address to be shifted by 1 */
> +	address = address << 1;

I understand this is from the existing code, but I would prefer this go
in the occ_i2c_write() implementation. Abstractions exist to hide
details.

What are your thoughts?

> +
> +	buf[0] = address;
> +	buf[1] = data1;
> +	buf[2] = data0;
> +
> +	rc = occ_i2c_write(bus, buf, sizeof(buf));

As above: I think this should be a call to ops->write(), or we need to
recognise that the read/write callbacks aren't useful.

> +	if (rc != sizeof(buf))
> +		return -I2C_WRITE_ERROR;
> +
> +	return 0;
> +}
> +
> +static int occ_i2c_probe(struct i2c_client *client,
> +			 const struct i2c_device_id *id)
> +{
> +	struct occ_bus_ops bus_ops;
> +
> +	bus_ops.read = occ_i2c_read;
> +	bus_ops.write = occ_i2c_write;
> +	bus_ops.getscom = occ_getscom;
> +	bus_ops.putscom = occ_putscom;
> +
> +	return occ_probe(&client->dev, bus_ops, client);
> +}
> +
> +static int occ_i2c_remove(struct i2c_client *client)
> +{
> +	return occ_remove(&client->dev);
> +}
> +
> +/* used by old-style board info. */
> +static const struct i2c_device_id occ_ids[] = {
> +	{ OCC_I2C_NAME, 0 },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, occ_ids);
> +
> +/* used by device table */
> +static const struct of_device_id occ_of_match[] = {
> +	{ .compatible = "ibm,occ-i2c" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, occ_of_match);
> +
> +/*
> + * i2c-core uses i2c-detect() to detect device in below address list.
> + * If exists, address will be assigned to client.
> + * It is also possible to read address from device table.
> + */
> +static const unsigned short normal_i2c[] = {0x50, 0x51, I2C_CLIENT_END };
> +
> +static struct i2c_driver occ_i2c_driver = {
> +	.class = I2C_CLASS_HWMON,
> +	.driver = {
> +		.name = OCC_I2C_NAME,
> +		.pm = NULL,
> +		.of_match_table = occ_of_match,
> +	},
> +	.probe = occ_i2c_probe,
> +	.remove = occ_i2c_remove,
> +	.id_table = occ_ids,
> +	.address_list = normal_i2c,
> +};
> +
> +module_i2c_driver(occ_i2c_driver);
> +
> +MODULE_AUTHOR("Eddie James <eajames at us.ibm.com>");
> +MODULE_DESCRIPTION("BMC OCC hwmon driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/hwmon/occ/power8_occ.c b/drivers/hwmon/occ/power8_occ.c
> index 6de0e76..7dec2e7 100644
> --- a/drivers/hwmon/occ/power8_occ.c
> +++ b/drivers/hwmon/occ/power8_occ.c
> @@ -1,8 +1,10 @@
>  /*
> - * OCC HWMON driver - read IBM Power8 On Chip Controller sensor data via
> - * i2c.
> + * power8_occ.c - Power8 OCC hwmon driver
>   *
> - * Copyright 2015 IBM Corp.
> + * This file contains the Power8-specific methods and data structures for
> + * the OCC hwmon driver.
> + *
> + * Copyright 2016 IBM Corp.
>   *
>   * This program is free software; you can redistribute it and/or modify
>   * it under the terms of the GNU General Public License as published by
> @@ -19,24 +21,14 @@
>  #include 
>  #include 
>  #include 
> -#include 
>  #include 
>  #include 
>  #include 
>  #include 
> -#include 
>  #include 
>  #include 
>  #include 
>  
> -#define OCC_I2C_ADDR 0x50
> -#define OCC_I2C_NAME "occ-i2c"
> -
> -#define OCC_DATA_MAX	4096 /* 4KB at most */
> -/* i2c read and write occ sensors */
> -#define I2C_READ_ERROR	1
> -#define I2C_WRITE_ERROR	2
> -
>  /* Defined in POWER8 Processor Registers Specification */
>  /* To generate attn to OCC */
>  #define ATTN_DATA	0x0006B035
> @@ -53,11 +45,11 @@
>  
>  #define MAX_SENSOR_ATTR_LEN	32
>  
> -enum sensor_t {
> -	freq,
> -	temp,
> -	power,
> -	caps,
> +enum sensor_type {
> +	FREQ = 0,
> +	TEMP,
> +	POWER,
> +	CAPS,

This isn't related to isolating the bus transfer protocol. I'd prefer
the change be a separate patch given this one, as it stands, is ~1300
lines.

>  	MAX_OCC_SENSOR_TYPE
>  };
>  
> @@ -125,7 +117,7 @@ struct occ_response {
>  };
>  
>  struct sensor_attr_data {
> -	enum sensor_t type;
> +	enum sensor_type type;
>  	uint32_t hwmon_index;
>  	uint32_t attr_id;
>  	char name[MAX_SENSOR_ATTR_LEN];
> @@ -138,112 +130,44 @@ struct sensor_group {
>  	struct attribute_group group;
>  };
>  
> -/* data private to each client */
> -struct occ_drv_data {
> -	struct i2c_client	*client;
> -	struct device		*hwmon_dev;
> -	struct mutex		update_lock;
> -	bool			valid;
> -	unsigned long		last_updated;
> -	/* Minimum timer interval for sampling In jiffies */
> -	unsigned long		update_interval;
> -	unsigned long		occ_online;
> -	uint16_t		user_powercap;
> -	struct occ_response	occ_resp;
> -	struct sensor_group	sensor_groups[MAX_OCC_SENSOR_TYPE];
> +struct power8_occ_driver {
> +	struct occ_driver *driver;
> +	struct device *dev;
> +	struct mutex update_lock;
> +	bool valid;
> +	unsigned long last_updated;
> +	unsigned long update_interval; /* minimum interval in jiffies */
> +	uint16_t user_powercap;
> +	struct occ_response response;
> +	struct sensor_group sensor_groups[MAX_OCC_SENSOR_TYPE];

Please do white space changes in a separate patch.

>  };
>  
> -static void deinit_occ_resp_buf(struct occ_response *p)
> +static void deinit_occ_resp_buf(struct occ_response *resp)

Please rename this in a separate patch.

>  {
>  	int i;
>  
> -	if (!p)
> +	if (!resp)
>  		return;
>  
> -	if (!p->blocks)
> +	if (!resp->blocks)
>  		return;
>  
> -	for (i = 0; i < p->header.sensor_block_num; i++) {
> -		kfree(p->blocks[i].sensor);
> -		kfree(p->blocks[i].power);
> -		kfree(p->blocks[i].caps);
> +	for (i = 0; i < resp->header.sensor_block_num; ++i) {
> +		kfree(resp->blocks[i].sensor);
> +		kfree(resp->blocks[i].power);
> +		kfree(resp->blocks[i].caps);
>  	}
>  
> -	kfree(p->blocks);
> -
> -	memset(p, 0, sizeof(*p));
> -
> -	for (i = 0; i < ARRAY_SIZE(p->sensor_block_id); i++)
> -		p->sensor_block_id[i] = -1;
> -}
> -
> -static ssize_t occ_i2c_read(struct i2c_client *client, void *buf, size_t count)
> -{
> -	WARN_ON(count > OCC_DATA_MAX);
> -
> -	dev_dbg(&client->dev, "i2c_read: reading %zu bytes @0x%x.\n",
> -		count, client->addr);
> -	return i2c_master_recv(client, buf, count);
> -}
> -
> -static ssize_t occ_i2c_write(struct i2c_client *client, const void *buf,
> -				size_t count)
> -{
> -	WARN_ON(count > OCC_DATA_MAX);
> -
> -	dev_dbg(&client->dev, "i2c_write: writing %zu bytes @0x%x.\n",
> -		count, client->addr);
> -	return i2c_master_send(client, buf, count);
> -}
> -
> -/* read 8-byte value and put into data[offset] */
> -static int occ_getscomb(struct i2c_client *client, uint32_t address,
> -		uint8_t *data, int offset)
> -{
> -	uint32_t ret;
> -	char buf[8];
> -	int i;
> -
> -	/* P8 i2c slave requires address to be shifted by 1 */
> -	address = address << 1;
> -
> -	ret = occ_i2c_write(client, &address,
> -		sizeof(address));
> -
> -	if (ret != sizeof(address))
> -		return -I2C_WRITE_ERROR;
> -
> -	ret = occ_i2c_read(client, buf, sizeof(buf));
> -	if (ret != sizeof(buf))
> -		return -I2C_READ_ERROR;
> -
> -	for (i = 0; i < 8; i++)
> -		data[offset + i] = buf[7 - i];
> -
> -	return 0;
> -}
> -
> -static int occ_putscom(struct i2c_client *client, uint32_t address,
> -		uint32_t data0, uint32_t data1)
> -{
> -	uint32_t buf[3];
> -	uint32_t ret;
> +	kfree(resp->blocks);
>  
> -	/* P8 i2c slave requires address to be shifted by 1 */
> -	address = address << 1;
> +	memset(resp, 0, sizeof(struct occ_response));
>  
> -	buf[0] = address;
> -	buf[1] = data1;
> -	buf[2] = data0;
> -
> -	ret = occ_i2c_write(client, buf, sizeof(buf));
> -	if (ret != sizeof(buf))
> -		return I2C_WRITE_ERROR;
> -
> -	return 0;
> +	for (i = 0; i < MAX_OCC_SENSOR_TYPE; ++i)
> +		resp->sensor_block_id[i] = -1;
>  }
>  
> -static void *occ_get_sensor_by_type(struct occ_response *resp, enum sensor_t t)
> +static void *occ_get_sensor_by_type(struct occ_response *resp,
> +				    enum sensor_type t)
>  {
>  	void *sensor;
>  
> @@ -254,14 +178,14 @@ static void *occ_get_sensor_by_type(struct occ_response *resp, enum sensor_t t)
>  		return NULL;
>  
>  	switch (t) {
> -	case temp:
> -	case freq:
> +	case TEMP:
> +	case FREQ:
>  		sensor = resp->blocks[resp->sensor_block_id[t]].sensor;
>  		break;
> -	case power:
> +	case POWER:
>  		sensor = resp->blocks[resp->sensor_block_id[t]].power;
>  		break;
> -	case caps:
> +	case CAPS:
>  		sensor = resp->blocks[resp->sensor_block_id[t]].caps;
>  		break;
>  	default:
> @@ -272,10 +196,10 @@ static void *occ_get_sensor_by_type(struct occ_response *resp, enum sensor_t t)
>  }
>  
>  static int occ_renew_sensor(struct occ_response *resp, uint8_t sensor_length,
> -	uint8_t sensor_num, enum sensor_t t, int block)
> +			    uint8_t sensor_num, enum sensor_type t, int block)
>  {
>  	void *sensor;
> -	int ret;
> +	int rc;

Another rename. Please split out to a separate patch

>  
>  	sensor = occ_get_sensor_by_type(resp, t);
>  
> @@ -286,40 +210,40 @@ static int occ_renew_sensor(struct occ_response *resp, uint8_t sensor_length,
>  	}
>  
>  	if (!sensor || sensor_num !=
> -			resp->blocks[resp->sensor_block_id[t]].sensor_num) {
> +	    resp->blocks[resp->sensor_block_id[t]].sensor_num) {
>  		kfree(sensor);
>  		switch (t) {
> -		case temp:
> -		case freq:
> +		case TEMP:
> +		case FREQ:
>  			resp->blocks[block].sensor =
> -				kcalloc(sensor_num,
> -					sizeof(struct occ_sensor), GFP_KERNEL);
> +				kcalloc(sensor_num, sizeof(struct occ_sensor),
> +					GFP_KERNEL);
>  			if (!resp->blocks[block].sensor) {
> -				ret = -ENOMEM;
> +				rc = -ENOMEM;
>  				goto err;
>  			}
>  			break;
> -		case power:
> +		case POWER:
>  			resp->blocks[block].power =
>  				kcalloc(sensor_num,
>  					sizeof(struct power_sensor),
>  					GFP_KERNEL);
>  			if (!resp->blocks[block].power) {
> -				ret = -ENOMEM;
> +				rc = -ENOMEM;
>  				goto err;
>  			}
>  			break;
> -		case caps:
> +		case CAPS:
>  			resp->blocks[block].caps =
> -				kcalloc(sensor_num,
> -					sizeof(struct caps_sensor), GFP_KERNEL);
> +				kcalloc(sensor_num, sizeof(struct caps_sensor),
> +					GFP_KERNEL);
>  			if (!resp->blocks[block].caps) {
> -				ret = -ENOMEM;
> +				rc = -ENOMEM;
>  				goto err;
>  			}
>  			break;
>  		default:
> -			ret = -ENOMEM;
> +			rc = -ENOMEM;
>  			goto err;
>  		}
>  	}
> @@ -327,7 +251,7 @@ static int occ_renew_sensor(struct occ_response *resp, uint8_t sensor_length,
>  	return 0;
>  err:
>  	deinit_occ_resp_buf(resp);
> -	return ret;
> +	return rc;
>  }
>  
>  #define RESP_DATA_LENGTH	3
> @@ -341,12 +265,12 @@ static inline uint16_t get_occdata_length(uint8_t *data)
>  	return be16_to_cpup((const __be16 *)&data[RESP_DATA_LENGTH]);
>  }
>  
> -static int parse_occ_response(struct i2c_client *client,
> -		uint8_t *data, struct occ_response *resp)
> +static int parse_occ_response(struct power8_occ_driver *driver, uint8_t *data,
> +			      struct occ_response *resp)
>  {
>  	int b;
>  	int s;
> -	int ret;
> +	int rc;

Please split this out to a separate patch.

>  	int dnum = SENSOR_BLOCK_OFFSET;
>  	struct occ_sensor *f_sensor;
>  	struct occ_sensor *t_sensor;
> @@ -357,19 +281,19 @@ static int parse_occ_response(struct i2c_client *client,
>  	uint8_t sensor_format;
>  	uint8_t sensor_length;
>  	uint8_t sensor_num;
> +	struct device *dev = driver->dev;

Please split this out to a separate patch.

>  
>  	/* check if the data is valid */
>  	if (strncmp(&data[SENSOR_STR_OFFSET], "SENSOR", 6) != 0) {
> -		dev_dbg(&client->dev,
> -			"ERROR: no SENSOR String in response\n");
> -		ret = -1;
> +		dev_dbg(dev, "ERROR: no SENSOR String in response\n");
> +		rc = -1;
>  		goto err;
>  	}
>  
>  	sensor_block_num = data[SENSOR_BLOCK_NUM_OFFSET];
>  	if (sensor_block_num == 0) {
> -		dev_dbg(&client->dev, "ERROR: SENSOR block num is 0\n");
> -		ret = -1;
> +		dev_dbg(dev, "ERROR: SENSOR block num is 0\n");
> +		rc = -1;
>  		goto err;
>  	}
>  
> @@ -377,93 +301,94 @@ static int parse_occ_response(struct i2c_client *client,
>  	if (sensor_block_num != resp->header.sensor_block_num) {
>  		deinit_occ_resp_buf(resp);
>  		resp->blocks = kcalloc(sensor_block_num,
> -			sizeof(struct sensor_data_block), GFP_KERNEL);
> +				       sizeof(struct sensor_data_block),
> +				       GFP_KERNEL);
>  		if (!resp->blocks)
>  			return -ENOMEM;
>  	}
>  
> -	memcpy(&resp->header, &data[RESP_HEADER_OFFSET], sizeof(resp->header));
> +	memcpy(&resp->header, &data[RESP_HEADER_OFFSET],
> +	       sizeof(struct occ_poll_header));

Separate patch

>  	resp->header.error_log_addr_start =
>  		be32_to_cpu(resp->header.error_log_addr_start);
>  	resp->header.error_log_length =
>  		be16_to_cpu(resp->header.error_log_length);
>  
> -	dev_dbg(&client->dev, "Reading %d sensor blocks\n",
> +	dev_dbg(dev, "Reading %d sensor blocks\n",
>  		resp->header.sensor_block_num);
>  	for (b = 0; b < sensor_block_num; b++) {
>  		/* 8-byte sensor block head */
>  		strncpy(sensor_type, &data[dnum], 4);
> -		sensor_format = data[dnum+5];
> -		sensor_length = data[dnum+6];
> -		sensor_num = data[dnum+7];
> +		sensor_format = data[dnum + 5];
> +		sensor_length = data[dnum + 6];
> +		sensor_num = data[dnum + 7];
>  		dnum = dnum + 8;
>  
> -		dev_dbg(&client->dev,
> -			"sensor block[%d]: type: %s, sensor_num: %d\n",
> -			b, sensor_type, sensor_num);
> +		dev_dbg(dev, "sensor block[%d]: type: %s, sensor_num: %d\n", b,
> +			sensor_type, sensor_num);
>  
>  		if (strncmp(sensor_type, "FREQ", 4) == 0) {
> -			ret = occ_renew_sensor(resp, sensor_length,
> -				sensor_num, freq, b);
> -			if (ret)
> +			rc = occ_renew_sensor(resp, sensor_length, sensor_num,
> +					      FREQ, b);
> +			if (rc)
>  				continue;
>  
> -			resp->sensor_block_id[freq] = b;
> +			resp->sensor_block_id[FREQ] = b;
>  			for (s = 0; s < sensor_num; s++) {
>  				f_sensor = &resp->blocks[b].sensor[s];
>  				f_sensor->sensor_id =
>  					be16_to_cpup((const __be16 *)
> -							&data[dnum]);
> +						     &data[dnum]);
>  				f_sensor->value = be16_to_cpup((const __be16 *)
> -							&data[dnum+2]);
> -				dev_dbg(&client->dev,
> +							      &data[dnum + 2]);
> +				dev_dbg(dev,
>  					"sensor[%d]-[%d]: id: %u, value: %u\n",
>  					b, s, f_sensor->sensor_id,
>  					f_sensor->value);
>  				dnum = dnum + sensor_length;
>  			}
>  		} else if (strncmp(sensor_type, "TEMP", 4) == 0) {
> -			ret = occ_renew_sensor(resp, sensor_length,
> -				sensor_num, temp, b);
> -			if (ret)
> +			rc = occ_renew_sensor(resp, sensor_length,
> +				sensor_num, TEMP, b);
> +			if (rc)
>  				continue;
>  
> -			resp->sensor_block_id[temp] = b;
> +			resp->sensor_block_id[TEMP] = b;
>  			for (s = 0; s < sensor_num; s++) {
>  				t_sensor = &resp->blocks[b].sensor[s];
>  				t_sensor->sensor_id =
>  					be16_to_cpup((const __be16 *)
> -							&data[dnum]);
> +						     &data[dnum]);
>  				t_sensor->value = be16_to_cpup((const __be16 *)
> -							&data[dnum+2]);
> -				dev_dbg(&client->dev,
> +							      &data[dnum + 2]);
> +				dev_dbg(dev,
>  					"sensor[%d]-[%d]: id: %u, value: %u\n",
>  					b, s, t_sensor->sensor_id,
>  					t_sensor->value);
>  				dnum = dnum + sensor_length;
>  			}
>  		} else if (strncmp(sensor_type, "POWR", 4) == 0) {
> -			ret = occ_renew_sensor(resp, sensor_length,
> -				sensor_num, power, b);
> -			if (ret)
> +			rc = occ_renew_sensor(resp, sensor_length,
> +				sensor_num, POWER, b);
> +			if (rc)
>  				continue;
>  
> -			resp->sensor_block_id[power] = b;
> +			resp->sensor_block_id[POWER] = b;
>  			for (s = 0; s < sensor_num; s++) {
>  				p_sensor = &resp->blocks[b].power[s];
>  				p_sensor->sensor_id =
>  					be16_to_cpup((const __be16 *)
> -							&data[dnum]);
> +						     &data[dnum]);
>  				p_sensor->update_tag =
>  					be32_to_cpup((const __be32 *)
> -							&data[dnum+2]);
> +						     &data[dnum + 2]);
>  				p_sensor->accumulator =
>  					be32_to_cpup((const __be32 *)
> -							&data[dnum+6]);
> +						     &data[dnum + 6]);
>  				p_sensor->value = be16_to_cpup((const __be16 *)
> -							&data[dnum+10]);
> +							     &data[dnum + 10]);
>  
> -				dev_dbg(&client->dev,
> +				dev_dbg(dev,
>  					"sensor[%d]-[%d]: id: %u, value: %u\n",
>  					b, s, p_sensor->sensor_id,
>  					p_sensor->value);
> @@ -471,55 +396,53 @@ static int parse_occ_response(struct i2c_client *client,
>  				dnum = dnum + sensor_length;
>  			}
>  		} else if (strncmp(sensor_type, "CAPS", 4) == 0) {
> -			ret = occ_renew_sensor(resp, sensor_length,
> -				sensor_num, caps, b);
> -			if (ret)
> +			rc = occ_renew_sensor(resp, sensor_length,
> +				sensor_num, CAPS, b);
> +			if (rc)
>  				continue;
>  
> -			resp->sensor_block_id[caps] = b;
> +			resp->sensor_block_id[CAPS] = b;
>  			for (s = 0; s < sensor_num; s++) {
>  				c_sensor = &resp->blocks[b].caps[s];
>  				c_sensor->curr_powercap =
>  					be16_to_cpup((const __be16 *)
> -							&data[dnum]);
> +						     &data[dnum]);
>  				c_sensor->curr_powerreading =
>  					be16_to_cpup((const __be16 *)
> -							&data[dnum+2]);
> +						     &data[dnum + 2]);
>  				c_sensor->norm_powercap =
>  					be16_to_cpup((const __be16 *)
> -							&data[dnum+4]);
> +						     &data[dnum + 4]);
>  				c_sensor->max_powercap =
>  					be16_to_cpup((const __be16 *)
> -							&data[dnum+6]);
> +						     &data[dnum + 6]);
>  				c_sensor->min_powercap =
>  					be16_to_cpup((const __be16 *)
> -							&data[dnum+8]);
> +						     &data[dnum + 8]);
>  				c_sensor->user_powerlimit =
>  					be16_to_cpup((const __be16 *)
> -							&data[dnum+10]);
> +						     &data[dnum + 10]);
>  
>  				dnum = dnum + sensor_length;
> -				dev_dbg(&client->dev, "CAPS sensor #%d:\n", s);
> -				dev_dbg(&client->dev, "curr_powercap is %x\n",
> +				dev_dbg(dev, "CAPS sensor #%d:\n", s);
> +				dev_dbg(dev, "curr_powercap is %x\n",
>  					c_sensor->curr_powercap);
> -				dev_dbg(&client->dev,
> -					"curr_powerreading is %x\n",
> +				dev_dbg(dev, "curr_powerreading is %x\n",
>  					c_sensor->curr_powerreading);
> -				dev_dbg(&client->dev, "norm_powercap is %x\n",
> +				dev_dbg(dev, "norm_powercap is %x\n",
>  					c_sensor->norm_powercap);
> -				dev_dbg(&client->dev, "max_powercap is %x\n",
> +				dev_dbg(dev, "max_powercap is %x\n",
>  					c_sensor->max_powercap);
> -				dev_dbg(&client->dev, "min_powercap is %x\n",
> +				dev_dbg(dev, "min_powercap is %x\n",
>  					c_sensor->min_powercap);
> -				dev_dbg(&client->dev, "user_powerlimit is %x\n",
> +				dev_dbg(dev, "user_powerlimit is %x\n",
>  					c_sensor->user_powerlimit);
>  			}
>  
>  		} else {
> -			dev_dbg(&client->dev,
> -				"ERROR: sensor type %s not supported\n",
> +			dev_dbg(dev, "ERROR: sensor type %s not supported\n",
>  				resp->blocks[b].sensor_type);
> -			ret = -1;
> +			rc = -1;
>  			goto err;
>  		}
>  
> @@ -532,15 +455,15 @@ static int parse_occ_response(struct i2c_client *client,
>  	return 0;
>  err:
>  	deinit_occ_resp_buf(resp);
> -	return ret;
> +	return rc;
>  }
>  
> -
> -/* Refer to OCC interface document for OCC command format
> +/*
> + * Refer to OCC interface document for OCC command format
>   * https://github.com/open-power/docs/blob/master/occ/OCC_OpenPwr_FW_Interfaces.pdf
>   */
> -static uint8_t occ_send_cmd(struct i2c_client *client, uint8_t seq,
> -		uint8_t type, uint16_t length, uint8_t *data, uint8_t *resp)
> +static uint8_t occ_send_cmd(struct occ_driver *occ, uint8_t seq, uint8_t type,
> +			    uint16_t length, uint8_t *data, uint8_t *resp)
>  {
>  	uint32_t cmd1, cmd2;
>  	uint16_t checksum;
> @@ -560,146 +483,152 @@ static uint8_t occ_send_cmd(struct i2c_client *client, uint8_t seq,
>  	cmd2 |= checksum << ((2 - length) * 8);
>  
>  	/* Init OCB */
> -	occ_putscom(client, OCB_STATUS_CONTROL_OR,  0x08000000, 0x00000000);
> -	occ_putscom(client, OCB_STATUS_CONTROL_AND, 0xFBFFFFFF, 0xFFFFFFFF);
> +	occ->bus_ops.putscom(occ->bus, OCB_STATUS_CONTROL_OR,  0x08000000,
> +			     0x00000000);
> +	occ->bus_ops.putscom(occ->bus, OCB_STATUS_CONTROL_AND, 0xFBFFFFFF,
> +			     0xFFFFFFFF);
>  
>  	/* Send command */
> -	occ_putscom(client, OCB_ADDRESS, OCC_COMMAND_ADDR, 0x00000000);
> -	occ_putscom(client, OCB_ADDRESS, OCC_COMMAND_ADDR, 0x00000000);
> -	occ_putscom(client, OCB_DATA, cmd1, cmd2);
> +	occ->bus_ops.putscom(occ->bus, OCB_ADDRESS, OCC_COMMAND_ADDR,
> +			     0x00000000);
> +	occ->bus_ops.putscom(occ->bus, OCB_ADDRESS, OCC_COMMAND_ADDR,
> +			     0x00000000);
> +	occ->bus_ops.putscom(occ->bus, OCB_DATA, cmd1, cmd2);
>  
>  	/* Trigger attention */
> -	occ_putscom(client, ATTN_DATA, 0x01010000, 0x00000000);
> +	occ->bus_ops.putscom(occ->bus, ATTN_DATA, 0x01010000, 0x00000000);
>  
>  	/* Get response data */
> -	occ_putscom(client, OCB_ADDRESS, OCC_RESPONSE_ADDR, 0x00000000);
> -	occ_getscomb(client, OCB_DATA, resp, 0);
> +	occ->bus_ops.putscom(occ->bus, OCB_ADDRESS, OCC_RESPONSE_ADDR,
> +			     0x00000000);
> +	occ->bus_ops.getscom(occ->bus, OCB_DATA, resp, 0);
>  
>  	/* return status */
>  	return resp[2];
>  }
>  
> -static int occ_get_all(struct i2c_client *client, struct occ_response *occ_resp)
> +static int occ_get_all(struct power8_occ_driver *driver)
>  {
> +	int i, rc;
>  	uint8_t *occ_data;
>  	uint16_t num_bytes;
> -	int i;
> -	int ret;
> -	uint8_t poll_cmd_data;
> -
> -	poll_cmd_data = 0x10;
> +	uint8_t poll_cmd_data = 0x10;
> +	struct device *dev = driver->dev;
> +	struct occ_driver *occ = driver->driver;
> +	struct occ_response *response = &driver->response;

Separate patch.

>  
>  	/*
>  	 * TODO: fetch header, and then allocate the rest of the buffer based
>  	 * on the header size. Assuming the OCC has a fixed sized header
>  	 */
> -	occ_data = devm_kzalloc(&client->dev, OCC_DATA_MAX, GFP_KERNEL);
> +	occ_data = devm_kzalloc(dev, OCC_DATA_MAX, GFP_KERNEL);
> +	if (!occ_data)
> +		return -ENOMEM;
>  
> -	ret = occ_send_cmd(client, 0, 0, 1, &poll_cmd_data, occ_data);
> -	if (ret) {
> -		dev_err(&client->dev, "ERROR: OCC Poll: 0x%x\n", ret);
> -		ret = -EINVAL;
> +	rc = occ_send_cmd(occ, 0, 0, 1, &poll_cmd_data, occ_data);
> +	if (rc) {
> +		dev_err(dev, "ERROR: OCC Poll: 0x%x\n", rc);
> +		rc = -EINVAL;
>  		goto out;
>  	}
>  
>  	num_bytes = get_occdata_length(occ_data);
>  
> -	dev_dbg(&client->dev, "OCC data length: %d\n", num_bytes);
> +	dev_dbg(dev, "OCC data length: %d\n", num_bytes);
>  
>  	if (num_bytes > OCC_DATA_MAX) {
> -		dev_dbg(&client->dev, "ERROR: OCC data length must be < 4KB\n");
> -		ret = -EINVAL;
> +		dev_dbg(dev, "ERROR: OCC data length must be < 4KB\n");
> +		rc = -EINVAL;
>  		goto out;
>  	}
>  
>  	if (num_bytes <= 0) {
> -		dev_dbg(&client->dev, "ERROR: OCC data length is zero\n");
> -		ret = -EINVAL;
> +		dev_dbg(dev, "ERROR: OCC data length is zero\n");
> +		rc = -EINVAL;
>  		goto out;
>  	}
>  
>  	/* read remaining data */
>  	for (i = 8; i < num_bytes + 8; i = i + 8)
> -		occ_getscomb(client, OCB_DATA, occ_data, i);
> +		occ->bus_ops.getscom(occ->bus, OCB_DATA, occ_data, i);
>  
> -	ret = parse_occ_response(client, occ_data, occ_resp);
> +	rc = parse_occ_response(driver, occ_data, occ_resp);
>  
>  out:
> -	devm_kfree(&client->dev, occ_data);
> -	return ret;
> +	devm_kfree(dev, occ_data);
> +	return rc;
>  }
>  
>  
> -static int occ_update_device(struct device *dev)
> +static int occ_update_device(struct power8_occ_driver *driver)

Do the (global) switch from struct device to struct power8_occ_driver
in a separate patch.

>  {
> -	struct occ_drv_data *data = dev_get_drvdata(dev);
> -	struct i2c_client *client = data->client;
> -	int ret = 0;
> -
> -	mutex_lock(&data->update_lock);
> -
> -	if (time_after(jiffies, data->last_updated + data->update_interval)
> -	    || !data->valid) {
> -		data->valid = 1;
> -		ret = occ_get_all(client, &data->occ_resp);
> -		if (ret)
> -			data->valid = 0;
> -		data->last_updated = jiffies;
> +	int rc = 0;
> +
> +	mutex_lock(&driver->update_lock);
> +
> +	if (time_after(jiffies, driver->last_updated + driver->update_interval)
> +	    || !driver->valid) {
> +		driver->valid = 1;
> +
> +		rc = occ_get_all(driver);
> +		if (rc)
> +			driver->valid = 0;
> +
> +		driver->last_updated = jiffies;
>  	}
> -	mutex_unlock(&data->update_lock);
>  
> -	return ret;
> +	mutex_unlock(&driver->update_lock);
> +
> +	return rc;
>  }
>  
>  
> -static void *occ_get_sensor(struct device *hwmon_dev, enum sensor_t t)
> +static void *occ_get_sensor(struct power8_occ_driver *driver,
> +			    enum sensor_type t)
>  {
> -	struct device *dev = hwmon_dev->parent;
> -	struct occ_drv_data *data = dev_get_drvdata(dev);
> -	int ret;
> +	int rc;
>  
> -	ret = occ_update_device(dev);
> -	if (ret != 0) {
> -		dev_dbg(dev, "ERROR: cannot get occ sensor data: %d\n", ret);
> +	rc = occ_update_device(driver);
> +	if (rc != 0) {
> +		dev_dbg(driver->dev, "ERROR: cannot get occ sensor data: %d\n",
> +			rc);
>  		return NULL;
>  	}
>  
> -	return occ_get_sensor_by_type(&data->occ_resp, t);
> +	return occ_get_sensor_by_type(&driver->response, t);
>  }
>  
> -static int occ_get_sensor_value(struct device *hwmon_dev, enum sensor_t t,
> -					int index)
> +static int occ_get_sensor_value(struct power8_occ_driver *driver,
> +				enum sensor_type t, int index)
>  {
>  	void *sensor;
>  
> -	if (t == caps)
> +	if (t == CAPS)
>  		return -1;
>  
> -	sensor = occ_get_sensor(hwmon_dev, t);
> -
> +	sensor = occ_get_sensor(driver, t);
>  	if (!sensor)
>  		return -1;
>  
> -	if (t == power)
> +	if (t == POWER)
>  		return ((struct power_sensor *)sensor)[index].value;
>  
>  	return ((struct occ_sensor *)sensor)[index].value;
>  }
>  
> -static int occ_get_sensor_id(struct device *hwmon_dev, enum sensor_t t,
> -					int index)
> +static int occ_get_sensor_id(struct power8_occ_driver *driver,
> +			     enum sensor_type t, int index)
>  {
>  	void *sensor;
>  
> -	if (t == caps)
> +	if (t == CAPS)
>  		return -1;
>  
> -	sensor = occ_get_sensor(hwmon_dev, t);
> -
> +	sensor = occ_get_sensor(driver, t);
>  	if (!sensor)
>  		return -1;
>  
> -	if (t == power)
> +	if (t == POWER)
>  		return ((struct power_sensor *)sensor)[index].sensor_id;
>  
>  	return ((struct occ_sensor *)sensor)[index].sensor_id;
> @@ -707,52 +636,56 @@ static int occ_get_sensor_id(struct device *hwmon_dev, enum sensor_t t,
>  
>  /* sysfs attributes for occ hwmon device */
>  
> -static ssize_t show_input(struct device *hwmon_dev,
> -				struct device_attribute *da, char *buf)
> +static ssize_t show_input(struct device *dev,

Roll the switch from 'hwmon_dev' to 'dev' into the patch that removes
the passing of struct device.

> +			  struct device_attribute *attr, char *buf)
>  {
> -	struct sensor_attr_data *sdata = container_of(da,
> -					struct sensor_attr_data, dev_attr);
>  	int val;
> -
> -	val = occ_get_sensor_value(hwmon_dev, sdata->type,
> -					sdata->hwmon_index - 1);
> -	if (sdata->type == temp)
> +	struct sensor_attr_data *sdata = container_of(attr,
> +						      struct sensor_attr_data,
> +						      dev_attr);
> +	struct power8_occ_driver *driver = dev_get_drvdata(dev);
> +
> +	val = occ_get_sensor_value(driver, sdata->type,
> +				   sdata->hwmon_index - 1);
> +	if (sdata->type == TEMP)
>  		/* in millidegree Celsius */
>  		val *= 1000;
>  
>  	return snprintf(buf, PAGE_SIZE - 1, "%d\n", val);
>  }
>  
> -static ssize_t show_label(struct device *hwmon_dev,
> -			struct device_attribute *da, char *buf)
> +static ssize_t show_label(struct device *dev,
> +			  struct device_attribute *attr, char *buf)
>  {
> -	struct sensor_attr_data *sdata = container_of(da,
> -					struct sensor_attr_data, dev_attr);
>  	int val;
> +	struct sensor_attr_data *sdata = container_of(da,
> +						      struct sensor_attr_data,
> +						      dev_attr);
> +	struct power8_occ_driver *driver = dev_get_drvdata(dev);
>  
> -	val = occ_get_sensor_id(hwmon_dev, sdata->type,
> -					sdata->hwmon_index - 1);
> +	val = occ_get_sensor_id(driver, sdata->type, sdata->hwmon_index - 1);
>  
>  	return snprintf(buf, PAGE_SIZE - 1, "%d\n", val);
>  }
>  
> -static ssize_t show_caps(struct device *hwmon_dev,
> -		struct device_attribute *da, char *buf)
> +static ssize_t show_caps(struct device *dev,
> +			 struct device_attribute *attr, char *buf)
>  {
> -	struct sensor_attr_data *sdata = container_of(da,
> -					struct sensor_attr_data, dev_attr);
> -	int nr = sdata->attr_id;
> -	int n = sdata->hwmon_index - 1;
> -	struct caps_sensor *sensor;
>  	int val;
> +	struct caps_sensor *sensor;
> +	struct sensor_attr_data *sdata = container_of(attr,
> +						      struct sensor_attr_data,
> +						      dev_attr);
> +	struct power8_occ_driver *driver = dev_get_drvdata(dev);
> +	int n = sdata->hwmon_index - 1;
>  
> -	sensor = occ_get_sensor(hwmon_dev, caps);
> +	sensor = occ_get_sensor(driver, CAPS);
>  	if (!sensor) {
>  		val = -1;
>  		return snprintf(buf, PAGE_SIZE - 1, "%d\n", val);
>  	}
>  
> -	switch (nr) {
> +	switch (sdata->attr_id) {
>  	case 0:
>  		val = sensor[n].curr_powercap;
>  		break;
> @@ -778,159 +711,139 @@ static ssize_t show_caps(struct device *hwmon_dev,
>  	return snprintf(buf, PAGE_SIZE - 1, "%d\n", val);
>  }
>  
> -static ssize_t show_update_interval(struct device *hwmon_dev,
> -				struct device_attribute *attr, char *buf)
> +static ssize_t show_update_interval(struct device *dev,
> +				    struct device_attribute *attr, char *buf)
>  {
> -	struct device *dev = hwmon_dev->parent;
> -	struct occ_drv_data *data = dev_get_drvdata(dev);
> +	struct power8_occ_driver *driver = dev_get_drvdata(dev);
>  
>  	return snprintf(buf, PAGE_SIZE - 1, "%u\n",
> -		jiffies_to_msecs(data->update_interval));
> +			jiffies_to_msecs(driver->update_interval));
>  }
>  
> -static ssize_t set_update_interval(struct device *hwmon_dev,
> -				struct device_attribute *attr,
> -				const char *buf, size_t count)
> +static ssize_t store_update_interval(struct device *dev,
> +				     struct device_attribute *attr,
> +				     const char *buf, size_t count)
>  {
> -	struct device *dev = hwmon_dev->parent;
> -	struct occ_drv_data *data = dev_get_drvdata(dev);
> +	struct power8_occ_driver *driver = dev_get_drvdata(dev);
>  	unsigned long val;
> -	int err;
> +	int rc;
>  
> -	err = kstrtoul(buf, 10, &val);
> -	if (err)
> -		return err;
> +	rc = kstrtoul(buf, 10, &val);
> +	if (rc)
> +		return rc;
> +
> +	driver->update_interval = msecs_to_jiffies(val);
>  
> -	data->update_interval = msecs_to_jiffies(val);
>  	return count;
>  }
> -static DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO,
> -		show_update_interval, set_update_interval);
>  
> -static ssize_t show_name(struct device *hwmon_dev,
> -				struct device_attribute *attr, char *buf)
> +static DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO, show_update_interval,
> +		   store_update_interval);
> +
> +static ssize_t show_name(struct device *devdev,
> +			 struct device_attribute *attr, char *buf)
>  {
>  	return snprintf(buf, PAGE_SIZE - 1, "%s\n", OCC_I2C_NAME);
>  }
> +
>  static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
>  
> -static ssize_t show_user_powercap(struct device *hwmon_dev,
> -				struct device_attribute *attr, char *buf)
> +static ssize_t show_user_powercap(struct device *dev,
> +				  struct device_attribute *attr, char *buf)
>  {
> -	struct device *dev = hwmon_dev->parent;
> -	struct occ_drv_data *data = dev_get_drvdata(dev);
> +	struct power8_occ_driver *driver = dev_get_drvdata(dev);
>  
> -	return snprintf(buf, PAGE_SIZE - 1, "%u\n", data->user_powercap);
> +	return snprintf(buf, PAGE_SIZE - 1, "%u\n", driver->user_powercap);
>  }
>  
> -
> -static ssize_t set_user_powercap(struct device *hwmon_dev,
> -				struct device_attribute *attr,
> -				const char *buf, size_t count)
> +static ssize_t store_user_powercap(struct device *dev,
> +				   struct device_attribute *attr,
> +				   const char *buf, size_t count)
>  {
> -	struct device *dev = hwmon_dev->parent;
> -	struct occ_drv_data *data = dev_get_drvdata(dev);
> -	struct i2c_client *client = data->client;
> +	struct power8_occ_driver *driver = dev_get_drvdata(dev);
>  	uint16_t val;
>  	uint8_t resp[8];
> -	int err;
> +	int rc;
>  
> -	err = kstrtou16(buf, 10, &val);
> -	if (err)
> -		return err;
> +	rc = kstrtou16(buf, 10, &val);
> +	if (rc)
> +		return rc;
>  
>  	dev_dbg(dev, "set user powercap to: %u\n", val);
>  	val = cpu_to_le16(val);
> -	err = occ_send_cmd(client, 0, 0x22, 2, (uint8_t *)&val, resp);
> -	if (err != 0) {
> +	rc = occ_send_cmd(client, 0, 0x22, 2, (uint8_t *)&val, resp);
> +	if (rc != 0) {
>  		dev_dbg(dev,
>  			"ERROR: Set User Powercap: wrong return status: %x\n",
> -			err);
> -		if (err == 0x13)
> +			rc);
> +		if (rc == 0x13)
>  			dev_info(dev,
> -				"ERROR: set invalid powercap value: %x\n", val);
> +				 "ERROR: set invalid powercap value: %x\n",
> +				 val);
>  		return -EINVAL;
>  	}
> -	data->user_powercap = val;
> +
> +	driver->user_powercap = val;
>  	return count;
>  }
> -static DEVICE_ATTR(user_powercap, S_IWUSR | S_IRUGO,
> -		show_user_powercap, set_user_powercap);
>  
> -static void deinit_sensor_groups(struct device *hwmon_dev,
> -					struct sensor_group *sensor_groups)
> +static DEVICE_ATTR(user_powercap, S_IWUSR | S_IRUGO, show_user_powercap,
> +		   store_user_powercap);
> +
> +static void deinit_sensor_groups(struct device *dev,
> +				 struct sensor_group *sensor_groups)
>  {
>  	int cnt;
>  
>  	for (cnt = 0; cnt < MAX_OCC_SENSOR_TYPE; cnt++) {
>  		if (sensor_groups[cnt].group.attrs)
> -			devm_kfree(hwmon_dev, sensor_groups[cnt].group.attrs);
> +			devm_kfree(dev, sensor_groups[cnt].group.attrs);
>  		if (sensor_groups[cnt].sattr)
> -			devm_kfree(hwmon_dev, sensor_groups[cnt].sattr);
> +			devm_kfree(dev, sensor_groups[cnt].sattr);
>  		sensor_groups[cnt].group.attrs = NULL;
>  		sensor_groups[cnt].sattr = NULL;
>  	}
>  }
>  
> -static void occ_remove_hwmon_attrs(struct device *hwmon_dev)
> -{
> -	struct occ_drv_data *data = dev_get_drvdata(hwmon_dev->parent);
> -	struct sensor_group *sensor_groups = data->sensor_groups;
> -	int i;
> -
> -	if (!hwmon_dev)
> -		return;
> -
> -	device_remove_file(hwmon_dev, &dev_attr_update_interval);
> -	device_remove_file(hwmon_dev, &dev_attr_name);
> -	device_remove_file(hwmon_dev, &dev_attr_user_powercap);
> -
> -	for (i = 0; i < MAX_OCC_SENSOR_TYPE; i++)
> -		sysfs_remove_group(&hwmon_dev->kobj, &sensor_groups[i].group);
> -
> -	deinit_sensor_groups(hwmon_dev, sensor_groups);
> -}
> -
>  static void sensor_attr_init(struct sensor_attr_data *sdata,
> -				char *sensor_group_name,
> -				char *attr_name,
> -				ssize_t (*show)(struct device *dev,
> -						struct device_attribute *attr,
> -						char *buf))
> +			     char *sensor_group_name,
> +			     char *attr_name,
> +			     ssize_t (*show)(struct device *dev,
> +					     struct device_attribute *attr,
> +					     char *buf))
>  {
>  	sysfs_attr_init(&sdata->dev_attr.attr);
>  
>  	snprintf(sdata->name, MAX_SENSOR_ATTR_LEN, "%s%d_%s",
> -		sensor_group_name, sdata->hwmon_index, attr_name);
> +		 sensor_group_name, sdata->hwmon_index, attr_name);
>  	sdata->dev_attr.attr.name = sdata->name;
>  	sdata->dev_attr.attr.mode = S_IRUGO;
>  	sdata->dev_attr.show = show;
>  }
>  
>  /* create hwmon sensor sysfs attributes */
> -static int create_sensor_group(struct device *hwmon_dev, enum sensor_t type,
> -				int sensor_num)
> +static int create_sensor_group(struct power8_occ_driver *driver,
> +			       enum sensor_type type, int sensor_num)
>  {
> -	struct occ_drv_data *data = dev_get_drvdata(hwmon_dev->parent);
> -	struct sensor_group *sensor_groups = data->sensor_groups;
> +	struct device *dev = driver->dev;
> +	struct sensor_group *sensor_groups = driver->sensor_groups;
>  	struct sensor_attr_data *sdata;
> -	int ret;
> -	int cnt;
> +	int rc, cnt;
>  
>  	/* each sensor has 'label' and 'input' attributes */
> -	sensor_groups[type].group.attrs = devm_kzalloc(hwmon_dev,
> -						sizeof(struct attribute *) *
> -						sensor_num * 2 + 1, GFP_KERNEL);
> +	sensor_groups[type].group.attrs =
> +		devm_kzalloc(dev, sizeof(struct attribute *) *
> +			     sensor_num * 2 + 1, GFP_KERNEL);
>  	if (!sensor_groups[type].group.attrs) {
> -		ret = -ENOMEM;
> +		rc = -ENOMEM;
>  		goto err;
>  	}
>  
> -	sensor_groups[type].sattr = devm_kzalloc(hwmon_dev,
> -					sizeof(struct sensor_attr_data) *
> -					sensor_num * 2, GFP_KERNEL);
> +	sensor_groups[type].sattr =
> +		devm_kzalloc(dev, sizeof(struct sensor_attr_data) *
> +			     sensor_num * 2, GFP_KERNEL);
>  	if (!sensor_groups[type].sattr) {
> -		ret = -ENOMEM;
> +		rc = -ENOMEM;
>  		goto err;
>  	}
>  
> @@ -940,45 +853,38 @@ static int create_sensor_group(struct device *hwmon_dev, enum sensor_t type,
>  		sdata->hwmon_index = cnt + 1;
>  		sdata->type = type;
>  		sensor_attr_init(sdata, sensor_groups[type].name, "input",
> -					show_input);
> +				 show_input);
>  		sensor_groups[type].group.attrs[cnt] = &sdata->dev_attr.attr;
>  
>  		sdata = &sensor_groups[type].sattr[cnt + sensor_num];
>  		sdata->hwmon_index = cnt + 1;
>  		sdata->type = type;
>  		sensor_attr_init(sdata, sensor_groups[type].name, "label",
> -					show_label);
> +				 show_label);
>  		sensor_groups[type].group.attrs[cnt + sensor_num] =
>  			&sdata->dev_attr.attr;
>  	}
>  
> -	ret = sysfs_create_group(&hwmon_dev->kobj, &sensor_groups[type].group);
> -	if (ret)
> +	rc = sysfs_create_group(&dev->kobj, &sensor_groups[type].group);
> +	if (rc)
>  		goto err;
>  
> -	return ret;
> +	return rc;
>  err:
> -	deinit_sensor_groups(hwmon_dev, sensor_groups);
> -	return ret;
> +	deinit_sensor_groups(dev, sensor_groups);
> +	return rc;
>  }
>  
>  static void caps_sensor_attr_init(struct sensor_attr_data *sdata,
> -					char *attr_name, uint32_t hwmon_index,
> -					uint32_t attr_id)
> +				  char *attr_name, uint32_t hwmon_index,
> +				  uint32_t attr_id)
>  {
> -	sdata->type = caps;
> +	sdata->type = CAPS;
>  	sdata->hwmon_index = hwmon_index;
>  	sdata->attr_id = attr_id;
>  
> -	/* FIXME, to be compatible with user space app, we do not
> -	 * generate caps1_* attributes.
> -	 */

Removing the fixme needs some justification. Probably best as a
separate patch if it is resolved.

> -	if (sdata->hwmon_index == 1)
> -		snprintf(sdata->name, MAX_SENSOR_ATTR_LEN, "%s_%s",
> -			"caps", attr_name);
> -	else
> -		snprintf(sdata->name, MAX_SENSOR_ATTR_LEN, "%s%d_%s",
> -			"caps", sdata->hwmon_index, attr_name);
> +	snprintf(sdata->name, MAX_SENSOR_ATTR_LEN, "%s%d_%s",
> +		 "caps", sdata->hwmon_index, attr_name);
>  
>  	sysfs_attr_init(&sdata->dev_attr.attr);
>  	sdata->dev_attr.attr.name = sdata->name;
> @@ -995,260 +901,148 @@ static char *caps_sensor_name[] = {
>  	"user_powerlimit",
>  };
>  
> -static int create_caps_sensor_group(struct device *hwmon_dev, int sensor_num)
> +static int create_caps_sensor_group(struct power8_occ_driver *driver,
> +				    int sensor_num)
>  {
> -	struct occ_drv_data *data = dev_get_drvdata(hwmon_dev->parent);
> -	struct sensor_group *sensor_groups = data->sensor_groups;
> +	struct device *dev = driver->dev;
> +	struct sensor_group *sensor_groups = driver->sensor_groups;
>  	int field_num = ARRAY_SIZE(caps_sensor_name);
>  	struct sensor_attr_data *sdata;
> -	int ret;
> -	int cnt;
> -	int i;
> +	int i, j, rc;
>  
> -	sensor_groups[caps].group.attrs = devm_kzalloc(hwmon_dev,
> -						sizeof(struct attribute *) *
> -						sensor_num * field_num + 1,
> -						GFP_KERNEL);
> -	if (!sensor_groups[caps].group.attrs) {
> -		ret = -ENOMEM;
> +	sensor_groups[CAPS].group.attrs =
> +		devm_kzalloc(dev, sizeof(struct attribute *) * sensor_num *
> +			     field_num + 1, GFP_KERNEL);
> +	if (!sensor_groups[CAPS].group.attrs) {
> +		rc = -ENOMEM;
>  		goto err;
>  	}
>  
> -	sensor_groups[caps].sattr = devm_kzalloc(hwmon_dev,
> -					sizeof(struct sensor_attr_data) *
> -					sensor_num * field_num,
> -					GFP_KERNEL);
> -	if (!sensor_groups[caps].sattr) {
> -		ret = -ENOMEM;
> +	sensor_groups[CAPS].sattr =
> +		devm_kzalloc(hwmon_dev, sizeof(struct sensor_attr_data) *
> +			     sensor_num * field_num, GFP_KERNEL);
> +	if (!sensor_groups[CAPS].sattr) {
> +		rc = -ENOMEM;
>  		goto err;
>  	}
>  
> -	for (cnt = 0; cnt < sensor_num; cnt++) {
> -		for (i = 0; i < field_num; i++) {
> -			sdata = &sensor_groups[caps].sattr[cnt * field_num + i];
> +	for (j = 0; j < sensor_num; ++j) {
> +		for (i = 0; i < field_num; ++i) {
> +			sdata = &sensor_groups[CAPS].sattr[j * field_num + i];
>  			caps_sensor_attr_init(sdata, caps_sensor_name[i],
> -						cnt + 1, i);
> -			sensor_groups[caps].group.attrs[cnt * field_num + i] =
> -						&sdata->dev_attr.attr;
> +					      j + 1, i);
> +			sensor_groups[CAPS].group.attrs[j * field_num + i] =
> +				&sdata->dev_attr.attr;
>  		}
>  	}
>  
> -	ret = sysfs_create_group(&hwmon_dev->kobj, &sensor_groups[caps].group);
> -	if (ret)
> +	rc = sysfs_create_group(&dev->kobj, &sensor_groups[CAPS].group);
> +	if (rc)
>  		goto err;
>  
> -	return ret;
> +	return rc;
>  err:
> -	deinit_sensor_groups(hwmon_dev, sensor_groups);
> -	return ret;
> +	deinit_sensor_groups(dev, sensor_groups);
> +	return rc;
>  }
>  
> -static int occ_create_hwmon_attrs(struct device *dev)
> +static void occ_remove_hwmon_attrs(struct power8_occ_driver *driver)
>  {
> -	struct occ_drv_data *drv_data = dev_get_drvdata(dev);
> -	struct device *hwmon_dev = drv_data->hwmon_dev;
> -	struct sensor_group *sensor_groups = drv_data->sensor_groups;
>  	int i;
> -	int sensor_num;
> -	int ret;
> -	struct occ_response *rsp;
> -	enum sensor_t t;
> +	struct device *dev = driver->dev;
> +	struct sensor_group *sensor_groups = driver->sensor_groups;
> +
> +	device_remove_file(dev, &dev_attr_user_powercap);
> +	device_remove_file(dev, &dev_attr_update_interval);
> +	device_remove_file(dev, &dev_attr_name);
>  
> -	rsp = &drv_data->occ_resp;
> +	for (i = 0; i < MAX_OCC_SENSOR_TYPE; i++)
> +		sysfs_remove_group(&dev->kobj, &sensor_groups[i].group);
> +
> +	deinit_sensor_groups(dev, sensor_groups);
> +}
> +
> +static int occ_create_hwmon_attrs(struct power8_occ_driver *driver)
> +{
> +	int i, sensor_num, rc, id;
> +	struct device *dev = driver->dev;
> +	struct sensor_group *sensor_groups = driver->sensor_groups;
> +	struct occ_response *response = &driver->response;
>  
> -	for (i = 0; i < ARRAY_SIZE(rsp->sensor_block_id); i++)
> -		rsp->sensor_block_id[i] = -1;
> +	for (i = 0; i < MAX_OCC_SENSOR_TYPE; ++i)
> +		response->sensor_block_id[i] = -1;
>  
>  	/* read sensor data from occ. */
> -	ret = occ_update_device(dev);
> -	if (ret != 0) {
> -		dev_dbg(dev, "ERROR: cannot get occ sensor data: %d\n", ret);
> -		return ret;
> +	rc = occ_update_device(driver);
> +	if (rc != 0) {
> +		dev_err(dev, "ERROR: cannot get occ sensor data: %d\n", rc);
> +		return rc;
>  	}
> -	if (!rsp->blocks)
> +	if (!response->blocks)
>  		return -1;
>  
> -	ret = device_create_file(hwmon_dev, &dev_attr_name);
> -	if (ret)
> +	rc = device_create_file(dev, &dev_attr_name);
> +	if (rc)
>  		goto error;
>  
> -	ret = device_create_file(hwmon_dev, &dev_attr_update_interval);
> -	if (ret)
> +	rc = device_create_file(dev, &dev_attr_update_interval);
> +	if (rc)
>  		goto error;
>  
> -	if (rsp->sensor_block_id[caps] >= 0) {
> +	if (response->sensor_block_id[CAPS] >= 0) {
>  		/* user powercap: only for master OCC */
> -		ret = device_create_file(hwmon_dev, &dev_attr_user_powercap);
> -		if (ret)
> +		rc = device_create_file(dev, &dev_attr_user_powercap);
> +		if (rc)
>  			goto error;
>  	}
>  
> -	sensor_groups[freq].name = "freq";
> -	sensor_groups[temp].name = "temp";
> -	sensor_groups[power].name = "power";
> -	sensor_groups[caps].name =  "caps";
> +	sensor_groups[FREQ].name = "freq";
> +	sensor_groups[TEMP].name = "temp";
> +	sensor_groups[POWER].name = "power";
> +	sensor_groups[CAPS].name =  "caps";
>  
> -	for (t = 0; t < MAX_OCC_SENSOR_TYPE; t++) {
> -		if (rsp->sensor_block_id[t] < 0)
> +	for (i = 0; i < MAX_OCC_SENSOR_TYPE; i++) {
> +		id = response->sensor_block_id[i];
> +		if (id < 0)
>  			continue;
>  
> -		sensor_num =
> -			rsp->blocks[rsp->sensor_block_id[t]].sensor_num;
> -		if (t == caps)
> -			ret = create_caps_sensor_group(hwmon_dev, sensor_num);
> +		sensor_num = response->blocks[id].sensor_num;
> +		if (i == CAPS)
> +			rc = create_caps_sensor_group(dev, sensor_num);
>  		else
> -			ret = create_sensor_group(hwmon_dev, t, sensor_num);
> -		if (ret)
> +			rc = create_sensor_group(dev, i, sensor_num);
> +		if (rc)
>  			goto error;
>  	}
>  
>  	return 0;
> -error:
> -	dev_err(dev, "ERROR: cannot create hwmon attributes\n");
> -	occ_remove_hwmon_attrs(drv_data->hwmon_dev);
> -	return ret;
> -}
> -
> -static ssize_t show_occ_online(struct device *dev,
> -				struct device_attribute *attr, char *buf)
> -{
> -	struct occ_drv_data *data = dev_get_drvdata(dev);
> -
> -	return snprintf(buf, PAGE_SIZE - 1, "%lu\n", data->occ_online);
> -}
> -
> -static ssize_t set_occ_online(struct device *dev,
> -				struct device_attribute *attr,
> -				const char *buf, size_t count)
> -{
> -	struct occ_drv_data *data = dev_get_drvdata(dev);
> -	unsigned long val;
> -	int err;
> -
> -	err = kstrtoul(buf, 10, &val);
> -	if (err)
> -		return err;
> -
> -	if (val == 1) {
> -		if (data->occ_online == 1)
> -			return count;
>  
> -		/* populate hwmon sysfs attr using sensor data */
> -		dev_dbg(dev, "occ register hwmon @0x%x\n", data->client->addr);
> -
> -		data->hwmon_dev = hwmon_device_register(dev);
> -		if (IS_ERR(data->hwmon_dev))
> -			return PTR_ERR(data->hwmon_dev);
> -
> -		err = occ_create_hwmon_attrs(dev);
> -		if (err) {
> -			hwmon_device_unregister(data->hwmon_dev);
> -			return err;
> -		}
> -		data->hwmon_dev->parent = dev;
> -	} else if (val == 0) {
> -		if (data->occ_online == 0)
> -			return count;
> -
> -		occ_remove_hwmon_attrs(data->hwmon_dev);
> -		hwmon_device_unregister(data->hwmon_dev);
> -		data->hwmon_dev = NULL;
> -	} else
> -		return -EINVAL;
> -
> -	data->occ_online = val;
> -	return count;
> -}
> -
> -static DEVICE_ATTR(online, S_IWUSR | S_IRUGO,
> -		show_occ_online, set_occ_online);
> -
> -static int occ_create_i2c_sysfs_attr(struct device *dev)
> -{
> -	/* create an i2c sysfs attribute, to indicate whether OCC is active */
> -	return device_create_file(dev, &dev_attr_online);
> +error:
> +	dev_err(dev, "ERROR: cannot create hwmon attributes: %d\n", rc);
> +	occ_remove_hwmon_attrs(driver);
> +	return rc;
>  }
>  
> -
> -/* device probe and removal */
> -
> -enum occ_type {
> -	occ_id,
> -};
> -
> -static int occ_probe(struct i2c_client *client, const struct i2c_device_id *id)
> +int occ_init(struct occ_driver *driver)
>  {
> -	struct device *dev = &client->dev;
> -	struct occ_drv_data *data;
> -
> -	data = devm_kzalloc(dev, sizeof(struct occ_drv_data), GFP_KERNEL);
> -	if (!data)
> +	struct device *dev = driver->hwmon;
> +	struct power8_occ_driver *power =
> +		devm_kzalloc(dev, sizeof(struct power_occ_driver),
> +			     GFP_KERNEL);
> +	if (!power)
>  		return -ENOMEM;
>  
> -	data->client = client;
> -	i2c_set_clientdata(client, data);
> -	mutex_init(&data->update_lock);
> -	data->update_interval = HZ;
> +	power->driver = driver;
> +	power->dev = dev;
>  
> -	occ_create_i2c_sysfs_attr(dev);
> +	set_dev_drvdata(dev, power);
>  
> -	dev_info(dev, "occ i2c driver ready: i2c addr at 0x%x\n", client->addr);
> -
> -	return 0;
> +	return occ_create_hwmon_attrs(driver);
>  }
>  
> -static int occ_remove(struct i2c_client *client)
> +void occ_exit(occ_driver *driver)
>  {
> -	struct occ_drv_data *data = i2c_get_clientdata(client);
> -
> -	/* free allocated sensor memory */
> -	deinit_occ_resp_buf(&data->occ_resp);
> -
> -	device_remove_file(&client->dev, &dev_attr_online);
> +	struct power8_occ_driver *power = dev_get_drvdata(driver->hwmon);
>  
> -	if (!data->hwmon_dev)
> -		return 0;
> -
> -	occ_remove_hwmon_attrs(data->hwmon_dev);
> -	hwmon_device_unregister(data->hwmon_dev);
> -	return 0;
> +	occ_remove_hwmon_attrs(power);
>  }
> -
> -/* used by old-style board info. */
> -static const struct i2c_device_id occ_ids[] = {
> -	{ OCC_I2C_NAME, occ_id, },
> -	{ /* LIST END */ }
> -};
> -MODULE_DEVICE_TABLE(i2c, occ_ids);
> -
> -/* use by device table */
> -static const struct of_device_id i2c_occ_of_match[] = {
> -	{.compatible = "ibm,occ-i2c"},
> -	{},
> -};
> -MODULE_DEVICE_TABLE(of, i2c_occ_of_match);
> -
> -/* i2c-core uses i2c-detect() to detect device in bellow address list.
> - *  If exists, address will be assigned to client.
> - * It is also possible to read address from device table.
> - */
> -static const unsigned short normal_i2c[] = {0x50, 0x51, I2C_CLIENT_END };
> -
> -static struct i2c_driver occ_driver = {
> -	.class		= I2C_CLASS_HWMON,
> -	.driver = {
> -		.name	= OCC_I2C_NAME,
> -		.pm	= NULL,
> -		.of_match_table = i2c_occ_of_match,
> -	},
> -	.probe		= occ_probe,
> -	.remove		= occ_remove,
> -	.id_table       = occ_ids,
> -	.address_list	= normal_i2c,
> -};
> -
> -module_i2c_driver(occ_driver);
> -
> -MODULE_AUTHOR("Li Yi <shliyi at cn.ibm.com>");
> -MODULE_DESCRIPTION("BMC OCC hwmon driver");
> -MODULE_LICENSE("GPL");
> diff --git a/drivers/hwmon/occ/power8_occ.h b/drivers/hwmon/occ/power8_occ.h
> new file mode 100644
> index 0000000..3f23d95
> --- /dev/null
> +++ b/drivers/hwmon/occ/power8_occ.h
> @@ -0,0 +1,24 @@
> +/*
> + * power8_occ.h - Power8 OCC hwmon driver
> + *
> + * This file contains Power8 specific function prototypes
> + *
> + * Copyright 2016 IBM Corp.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#ifndef __POWER8_OCC_H__
> +#define __POWER8_OCC_H__
> +
> +int occ_init(struct occ_driver *driver);
> +
> +#endif /* __POWER8_OCC_H__ */

I was suffering review fatigue by the end, so the lack of comments
doesn't necessary mean a lack of issues, but in the interest of sending
this sooner rather than later I'll try to come back to it.

The changes have a much higher chance of being accepted if they are
provided as concise patches. The fact that your overview contains four
bullet points:

> Patch 2: "drivers: occ hwmon - isolate bus transfer protocol"
> * modify drivers/hwmon Makefile and Kconfig
> * create i2c layer
> * move some common code out of the Power8 OCC specific file
> * clean up Power8 OCC driver
> 

Indicates this one change might be at least four patches.

Andrew
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